The present invention relates to distributing apparatus and particularly to an apparatus which is designed to divide a single, two-phase, vapor-liquid stream into a plurality of individual streams in which each of the individual streams has substantially an equal ratio of vapor to liquid. In many processes a main two-phase, vapor-liquid flow must be divided into several individual streams while maintaining an equal liquid-vapor ratio in the individual streams. For example, a central facility may be used to supply process heat in the form of high-quality, two-phase steam to several individual processes or locations. It is necessary that the main stream flow be divided into several individual flows to supply the individual location. It is obvious that one must maintain an equal vapor-liquid ratio in each of the individual branch flows or the individual flows may consist primarily of water and very little steam or vice versa.
In thermal enhanced oil recovery (EOR) projects steam is injected into hydrocarbon bearing formations to increase production. In these systems it is very common to use high-quality, two-phase steam, for example, 80% quality steam. The practice of generating two-phase steam is necessitated by the use of low quality or brackish (produced) waters with moderate dissolved solids contents in the process. To prevent deposition of salts on the surfaces of the steam generator tubes, it is necessary to retain part of the flow in a liquid state in order to maintain the solids and other impurities in solution. If it is necessary to distribute this steam to individual injection wells, the problem arises of dividing the main flow into the individual flows while maintaining the ratio between vapor and water in the individual flows.
The above problem of thermal EOR projects will increase when large cogeneration plants are installed. The cogeneration plants will produce both electricity and the steam required for the thermal EOR projects. These plants will be centralized and the initial steam flow will be large and must be divided into the individual flows for various injection wells. These centralized plants will require that the initial distribution of steam be through large diameter main flowlines.
In the prior art, for example, U.S. Pat. No. 3,899,000 suggests that a two-phase vapor-liquid mixture could be separated into two or more individual flows by use of a closed vessel. The vessel is mounted vertically and provided with a top inlet and two or more bottom outlets. A flat horizontal baffle is used to divert the inlet flow from the open ends of the outlets. The axis of the inlet and the axis of the outlets are substantially parallel so the flow of the fluid is axially through an elongated vessel. The vapor-liquid ratio is maintained by using the outlets as standpipes and the vessel as a reservoir. Once sufficient liquid collects in the bottom of the vessel it can overflow side outlets in the standpipes and liquid will be added to the vapor flowing out of the outlets. While this system may be satisfactory it does rely upon the condensed liquid partially separating from the vapor with subsequent recombination with the vapor. This will be ineffective if the vessel is not vertical and unequal distribution of liquid and vapor can result. Also, the use of baffles to change the flow direction can cause excessive pressure losses.